Not nonsense, i've done extensive research and you probably have not even tried to look at it if that's what you think of the idea. There's something to be said for questioning and debate rather than straight insults if somebody says something that you don't understand.
You can take it at a 0-10ilvl upgrade if you're running only 222 (depending on your gear, haste amount, amount of critical chaos relics etc) but for the highest DPS talents either way to perform better it needs to be +~25ilvl.
There is a reason that some of the top havoc logs in mythic and heroic are using t19, it's not because they didn't find equal ilvl tier 20 yet. That's easy to find, even T20H drops 10ilvls higher than T19M base.
If not from me then take it from the havoc discord and Zarania -
https://us.battle.net/forums/en/wow/topic/20758396028